I have several times encountered an issue where Audacity becomes completely unresponsive, and all the menu items become grey, and the only way out of it is to force quit the application.I don’t remember what I was doing just before it happened this time, but it wasn’t anything especially processor intensive. I have saved a log and can post it if required.
Did you see the beachball?
I’m guessing it’s not CPU related, but RAM related. It could be you system running out of ram. Swapping out to disk can cause serious delays.
The first thing to check is if there are any background tasks not needed that are running. I’l thinking of stuff like the HP scanner driver for a scanner that you no longer need. I’m thinking of HP because it is an old and notorious bad driver and I had to reinstall it myself to scan one document recently. I had to uninstall it afterwards, because it ate up a lot of CPU when doing nothing.
A tool you can use to take a listing of your installed software, is etrecheck. See:
If you post that listing here, we can have a look at what is eating your system.
A log from Audacity or OSX might be helpful too.
Do you know about Activity Monitor?
Go > Utilities > Activity Monitor. I keep a copy of it in the dock and run it when I think there’s something odd.
That’s how I found one of the newspapers I read was taking 175% of the CPU (two processors) in formatting, logging, animations, commercials, customer info, nudgeware and a couple I never figured out. I wondered why the computer was getting hot while I was reading a text page with two still graphics.
Do you get the Spinning Beach Ball Of Death? That’s when the system takes more time than is allocated to complete a job.
On top of that, Audacity can get very slow fitting and zooming projects containing more than an hour of audio.
That’s what I seemed to remember.
It’s not even enough for installing El Capitan without resorting to tricks. Been there, done that. But not for users that record audio or handle video. That would require a slimmed down setup and that is an awful lot of tedious work.